Birdsong - some things to look out for?

There was an interesting seminar at the University yesterday, given by Sarah Collins (Plymouth University) on “Fighting & Flirting: the Function of Birdsong”. The evolution of birdsong is driven by female choice and male competition. In other words, the deliverer has to appear sexy to females and scary to males. Apparently, some birds such as the starling and the great tit use the same song, others such as wood warblers use a simple song to attract females and a complex song to repel males, while others use a different part of the same song for the two functions. Using observations based on playbacks, it's been found that in the chaffinch, the trill deters males and the end bit attracts females. Rather more convincingly, in the blackcap, the warble attracts females and the whistle deters males. Before pairing, there are more warbles and after pairing, there are more whistles. In joint work with Spain, they found that migratory blackcaps have more warbles than sedentary blackcaps.